Multi-component coating compositions are widely used in the plastics and marine industries. In these compositions, a liquid resin system and a catalyst for the resin system are mixed together and are sprayed onto a substrate such that the catalyst and the resin system react and harden on the substrate. The mixing may be done immediately before spraying (referred to as an internal mixing system) or immediately after spraying (referred to as an external mixing system). For example, U.S. Pat. No. 4,967,956 to Mansfield discloses a "gel coat" spraying system which uses a resin such as an epoxy resin or a polyester resin, a catalyst for the resin, and spraying means which includes an airless liquid nozzle. Such a gel coat utilizes a slow curing process.
Conventional coating compositions on articles often produce gray marks when the coating is scratched or contacted with a blunt instrument. When these marks form, the article is referred to as being "marred." Although it is not known for certain how the gray mar marks are produced, one possible explanation is that the mar is produced as a result of the coating being too soft to resist damage to its chemical structure. Another possible explanation is that when the coating is scratched, the bonds between the molecules which make up the coating are broken and produce the gray mar.
Additionally, conventional coatings can become damaged by the penetration of water and other chemicals into the chemical structure of the coating. These coatings allow water penetration because of open spaces in the polymeric structure of the coating which are produced during the polymerization reaction which forms the coating. Water penetrates into these openings and then expands when it freezes. The expansion of the water then causes the coating to crack and pit.
Accordingly, a need in the art still exists for a sprayable coating composition which may be easily applied to a variety of substrates, cures quickly, and has an improved water and mar resistance.